Conventionally, material data such as video data and audio data that are photographed and sound-recorded are recorded on a tape device such as a video tape that is a record medium. In recent years, as the information process technologies have been advanced, information has been digitized and discs such as DVD (Digital Versatile Disc) and so forth have been used as record mediums.
In these record mediums, material data are managed as files according to a file system such as UDF (Universal Disk Format). Thus, when material data are reproduced, a reproduction apparatus searches a record medium for a file of material data with a path name (hereinafter referred to as an absolute path name) and a file name under the root directory, reads the file from the record medium, and reproduces the file.
However, in this search method using an absolute path name and a file name, the absolute path name and the file name are used only for the local disc.
When an information process apparatus reads a file from an optical disc as a record medium loaded thereinto and records the file to an internal hard disk thereof, since the hard disk stores other information not recorded on the optical disc and the directory structure of the hard disk is different from that of the optical disc, the information process apparatus cannot access a file recorded on the hard disk with the same absolute path name and file name as those of the optical disc.
When a first file recorded on the optical disc references a second file different from the first file with an absolute path name and a file name, if the directory of the second file is changed the absolute path name of the second file described in the first file needs to be updated as the directory of the second path is changed. Otherwise, the first file cannot reference the second file.
In addition, when the information process apparatus reads the first file and the second file from the optical disc and records these files to the internal hard disc thereof, as described above, since the absolute path names of the first file and the second file recorded on the hard disc are different from those of the optical disc, unless the absolute path name of the second file described in the first file is updated, it cannot reference the second file.
If the first file references the second file with a path based on the position of the first file (hereinafter this path is referred to as a relative path name) and a file name and the information process apparatus records the first file and the second file to the hard disc so that the information process apparatus holds the relative path name, the first file can preference the second file. However, when the second file is moved to a different directory, the first file needs to be updated.
In contrast, a method that identifies material data (file) with a UMID (Unique Material IDentifier) is known. The UMID is a standardized identifier established by SMPTE (Society of Motion Picture and Television Engineers) and globally and uniquely identifies AV (Audio Visual) material or the like.
For example, a table that describes the relationship of path names and file names of files and UMIDs assigned to these files is recorded on an optical disc and a hard disk so that a UMID is converted into a path name and a file name. Thus, the information process apparatus can easily identify a file with a UMID in any directory structure.
When the first file references the second file with an UMID, since the relationship of path names, file names, and UMIDs are totally managed with the table, even if any file is moved, it can be easily identified only by updating the table.
However, since the foregoing UMID is an identifier that globally and uniquely identifies AV material or the like, even a basic UMID composed of basic information has a data amount of 32 bytes. The data amount of an extended UMID of which user information and so forth are added to the basic UMID becomes 64 bytes. This data amount is very large as an ID. Thus, when material data are identified with an UMID, the total data amount increases. In addition, the load for the process that identifies material data in the reproduction process and the record process becomes heavy.